Fix bug in DTMF generation where events with level > 36 would be ignored.

webrtc/modules/audio_coding/neteq/dtmf_tone_generator.cc

Index: webrtc/modules/audio_coding/neteq/dtmf_tone_generator.cc
diff --git a/webrtc/modules/audio_coding/neteq/dtmf_tone_generator.cc b/webrtc/modules/audio_coding/neteq/dtmf_tone_generator.cc
index f4d5190c615ab2c0ecd3eddd007b6c1301522ce8..2cafeec9b77fe4323b654540265b2c8b1b0b6e68 100644
--- a/webrtc/modules/audio_coding/neteq/dtmf_tone_generator.cc
+++ b/webrtc/modules/audio_coding/neteq/dtmf_tone_generator.cc
@@ -124,7 +124,7 @@ int DtmfToneGenerator::Init(int fs, int event, int attenuation) {
     return kParameterError;  // Invalid event number.
   }
 
-  if (attenuation < 0 || attenuation > 36) {
+  if (attenuation < 0 || attenuation > 63) {
     return kParameterError;  // Invalid attenuation.
   }